CN113078078A - Wafer cleaning method and wafer cleaning device - Google Patents
Wafer cleaning method and wafer cleaning device Download PDFInfo
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- CN113078078A CN113078078A CN202110294823.XA CN202110294823A CN113078078A CN 113078078 A CN113078078 A CN 113078078A CN 202110294823 A CN202110294823 A CN 202110294823A CN 113078078 A CN113078078 A CN 113078078A
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- 238000004140 cleaning Methods 0.000 title claims abstract description 108
- 238000000034 method Methods 0.000 title claims abstract description 72
- 238000005498 polishing Methods 0.000 claims abstract description 72
- 239000004094 surface-active agent Substances 0.000 claims abstract description 49
- 239000003344 environmental pollutant Substances 0.000 claims abstract description 43
- 231100000719 pollutant Toxicity 0.000 claims abstract description 43
- 230000008569 process Effects 0.000 claims abstract description 29
- 238000005201 scrubbing Methods 0.000 claims abstract description 24
- 238000005507 spraying Methods 0.000 claims abstract description 17
- 239000000356 contaminant Substances 0.000 claims description 39
- 239000012459 cleaning agent Substances 0.000 claims description 35
- 239000000126 substance Substances 0.000 claims description 21
- 238000004506 ultrasonic cleaning Methods 0.000 claims description 19
- 239000002253 acid Substances 0.000 claims description 16
- 230000002378 acidificating effect Effects 0.000 claims description 16
- 238000005406 washing Methods 0.000 claims description 14
- 230000003993 interaction Effects 0.000 claims description 11
- 238000007517 polishing process Methods 0.000 claims description 11
- 239000000758 substrate Substances 0.000 claims description 8
- 230000009471 action Effects 0.000 claims description 7
- CETPSERCERDGAM-UHFFFAOYSA-N ceric oxide Chemical compound O=[Ce]=O CETPSERCERDGAM-UHFFFAOYSA-N 0.000 claims description 5
- 229910000422 cerium(IV) oxide Inorganic materials 0.000 claims description 5
- 230000003647 oxidation Effects 0.000 claims description 5
- 238000007254 oxidation reaction Methods 0.000 claims description 5
- 230000010399 physical interaction Effects 0.000 claims description 5
- 239000002002 slurry Substances 0.000 claims description 4
- QAOWNCQODCNURD-UHFFFAOYSA-L sulfate group Chemical group S(=O)(=O)([O-])[O-] QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 claims description 4
- BDHFUVZGWQCTTF-UHFFFAOYSA-M sulfonate Chemical compound [O-]S(=O)=O BDHFUVZGWQCTTF-UHFFFAOYSA-M 0.000 claims description 4
- 230000000704 physical effect Effects 0.000 claims 1
- 230000000694 effects Effects 0.000 abstract description 10
- 239000004065 semiconductor Substances 0.000 abstract description 9
- 239000000853 adhesive Substances 0.000 abstract 1
- 230000001070 adhesive effect Effects 0.000 abstract 1
- WGTYBPLFGIVFAS-UHFFFAOYSA-M tetramethylammonium hydroxide Chemical compound [OH-].C[N+](C)(C)C WGTYBPLFGIVFAS-UHFFFAOYSA-M 0.000 description 8
- 230000007547 defect Effects 0.000 description 5
- 239000002245 particle Substances 0.000 description 5
- KRHYYFGTRYWZRS-UHFFFAOYSA-N Fluorane Chemical compound F KRHYYFGTRYWZRS-UHFFFAOYSA-N 0.000 description 4
- MHAJPDPJQMAIIY-UHFFFAOYSA-N Hydrogen peroxide Chemical compound OO MHAJPDPJQMAIIY-UHFFFAOYSA-N 0.000 description 4
- 229910052684 Cerium Inorganic materials 0.000 description 3
- -1 cerium ions Chemical class 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 3
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 2
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- 238000005034 decoration Methods 0.000 description 2
- 230000002950 deficient Effects 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 230000005611 electricity Effects 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 230000009467 reduction Effects 0.000 description 2
- 239000007921 spray Substances 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- VHUUQVKOLVNVRT-UHFFFAOYSA-N Ammonium hydroxide Chemical compound [NH4+].[OH-] VHUUQVKOLVNVRT-UHFFFAOYSA-N 0.000 description 1
- 229910021529 ammonia Inorganic materials 0.000 description 1
- 235000011114 ammonium hydroxide Nutrition 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 230000003628 erosive effect Effects 0.000 description 1
- 238000005530 etching Methods 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 230000003472 neutralizing effect Effects 0.000 description 1
- 230000002035 prolonged effect Effects 0.000 description 1
- 235000012239 silicon dioxide Nutrition 0.000 description 1
- 239000000377 silicon dioxide Substances 0.000 description 1
Images
Classifications
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/67—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere
- H01L21/67005—Apparatus not specifically provided for elsewhere
- H01L21/67011—Apparatus for manufacture or treatment
- H01L21/67017—Apparatus for fluid treatment
- H01L21/67028—Apparatus for fluid treatment for cleaning followed by drying, rinsing, stripping, blasting or the like
- H01L21/6704—Apparatus for fluid treatment for cleaning followed by drying, rinsing, stripping, blasting or the like for wet cleaning or washing
- H01L21/67046—Apparatus for fluid treatment for cleaning followed by drying, rinsing, stripping, blasting or the like for wet cleaning or washing using mainly scrubbing means, e.g. brushes
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B08—CLEANING
- B08B—CLEANING IN GENERAL; PREVENTION OF FOULING IN GENERAL
- B08B3/00—Cleaning by methods involving the use or presence of liquid or steam
- B08B3/02—Cleaning by the force of jets or sprays
- B08B3/022—Cleaning travelling work
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B08—CLEANING
- B08B—CLEANING IN GENERAL; PREVENTION OF FOULING IN GENERAL
- B08B3/00—Cleaning by methods involving the use or presence of liquid or steam
- B08B3/04—Cleaning involving contact with liquid
- B08B3/08—Cleaning involving contact with liquid the liquid having chemical or dissolving effect
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B08—CLEANING
- B08B—CLEANING IN GENERAL; PREVENTION OF FOULING IN GENERAL
- B08B3/00—Cleaning by methods involving the use or presence of liquid or steam
- B08B3/04—Cleaning involving contact with liquid
- B08B3/10—Cleaning involving contact with liquid with additional treatment of the liquid or of the object being cleaned, e.g. by heat, by electricity or by vibration
- B08B3/12—Cleaning involving contact with liquid with additional treatment of the liquid or of the object being cleaned, e.g. by heat, by electricity or by vibration by sonic or ultrasonic vibrations
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/02041—Cleaning
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/67—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere
- H01L21/67005—Apparatus not specifically provided for elsewhere
- H01L21/67011—Apparatus for manufacture or treatment
- H01L21/67017—Apparatus for fluid treatment
- H01L21/67028—Apparatus for fluid treatment for cleaning followed by drying, rinsing, stripping, blasting or the like
- H01L21/6704—Apparatus for fluid treatment for cleaning followed by drying, rinsing, stripping, blasting or the like for wet cleaning or washing
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- Engineering & Computer Science (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Condensed Matter Physics & Semiconductors (AREA)
- General Physics & Mathematics (AREA)
- Manufacturing & Machinery (AREA)
- Computer Hardware Design (AREA)
- Physics & Mathematics (AREA)
- Power Engineering (AREA)
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- General Chemical & Material Sciences (AREA)
- Cleaning Or Drying Semiconductors (AREA)
- Mechanical Treatment Of Semiconductor (AREA)
Abstract
The invention relates to a wafer cleaning method and a wafer cleaning device. The wafer cleaning method comprises the following steps: providing a wafer to be cleaned, wherein the surface of the wafer is provided with pollutants; and spraying a surfactant to the surface of the wafer while scrubbing the surface of the wafer by using a polishing pad, wherein the surfactant can act on the pollutants on the surface of the wafer to reduce the adhesion between the pollutants and the wafer, so that the pollutants on the surface of the wafer are removed. The invention can remove most even all the pollutants remained on the surface of the wafer in the front-end process, and the adhesive force between the pollutants and the wafer is reduced, so that the probability of the pollutants sticking back to the surface of the wafer is reduced, the cleaning effect of the wafer is improved, the residues of the pollutants on the surface of the wafer are reduced, and the smooth and stable operation of the semiconductor process is ensured.
Description
Technical Field
The invention relates to the technical field of semiconductor manufacturing, in particular to a wafer cleaning method and a wafer cleaning device.
Background
Chemical Mechanical Polishing (CMP) is an important process step in semiconductor manufacturing. After the chemical mechanical polishing process is completed, the polished wafer generally needs to be cleaned to remove polishing residues on the wafer surface. In current post-polish cleaning processes, the wafer surface is typically scrubbed with a cleaning brush. When the cleaning of the cleaning brush is completed and the cleaning brush is separated from the wafer (i.e. at the moment when the cleaning brush is opened), due to the limitation of the structure of the cleaning brush, the defect sources such as particles on the cleaning brush can be easily adhered back to the surface of the wafer, so that the fan-shaped or rod-shaped special pattern defects are formed on the surface of the wafer. And as the service life of the cleaning brush is prolonged, the bearing capacity of the defect sources on the cleaning brush is larger and larger, so that the defect sources are easier to fall to the surface of the wafer at the moment when the cleaning brush is opened. The defect source falls off or is adhered back, so that the pollutants are remained on the surface of the wafer, the cleaning effect of the wafer is reduced, and the smooth proceeding of the subsequent semiconductor processing process is influenced.
Therefore, how to improve the wafer cleaning effect, reduce the residual of the contaminants on the wafer surface, and ensure the smooth and stable progress of the semiconductor process is a technical problem to be solved.
Disclosure of Invention
The invention provides a wafer cleaning method and a wafer cleaning device, which are used for solving the problem of poor wafer cleaning effect in the prior art, reducing the residue of pollutants on the surface of a wafer and ensuring the smooth and stable operation of a semiconductor processing procedure.
In order to solve the above problems, the present invention provides a wafer cleaning method, comprising the steps of:
providing a wafer to be cleaned, wherein the surface of the wafer is provided with pollutants;
and spraying a surfactant to the surface of the wafer while scrubbing the surface of the wafer by using a polishing pad, wherein the surfactant can act on the pollutants on the surface of the wafer to reduce the adhesion between the pollutants and the wafer, so that the pollutants on the surface of the wafer are removed.
Optionally, the interaction between the surfactant and the contaminants on the wafer surface is a chemical interaction or a physical interaction.
Optionally, the specific steps of scrubbing the surface of the wafer by using the polishing pad include:
the wafer and the polishing pad are driven to rotate respectively, and the rotation directions of the wafer and the polishing pad are the same.
Optionally, the specific steps of scrubbing the surface of the wafer by using the polishing pad include:
and driving the wafer to rotate and driving the polishing pad to reciprocate on the surface of the wafer along a preset path.
Optionally, the wafer includes a substrate and an oxide layer on the substrate, and the contaminant is a contaminant remaining after the oxide layer is subjected to a chemical mechanical polishing process; the specific steps of scrubbing the wafer by adopting a surfactant and combining with mechanical external force comprise:
and scrubbing the oxide layer by adopting a surfactant and combining with mechanical external force.
Optionally, the polishing slurry used in the chemical mechanical polishing process is cerium dioxide, and the surfactant is a sulfate or a sulfonate.
Optionally, the mass concentration of the surfactant is less than 1%.
Optionally, after the wafer is scrubbed by using a surfactant and combining with a mechanical external force, the method further includes the following steps:
and cleaning the wafer by adopting an ultrasonic cleaning process.
Optionally, after the wafer is cleaned by using the ultrasonic cleaning process, the method further includes the following steps:
and washing the wafer by adopting an acid cleaning agent.
Optionally, the specific steps of washing the wafer with an acidic cleaning agent include:
and spraying an acid cleaning agent to the surface of the wafer while driving the wafer to rotate, so as to remove a natural oxidation layer on the surface of the wafer.
Optionally, after the wafer is rinsed with the acidic cleaning agent, the method further includes the following steps:
and washing the wafer by adopting an alkaline cleaning agent.
Optionally, the wafer is washed by an alkaline cleaning agent without using a cleaning brush.
In order to solve the above problems, the present invention also provides a wafer cleaning apparatus, comprising:
the spraying module is used for spraying a surfactant to a wafer with a pollutant on the surface, and the surfactant can act on the pollutant on the surface of the wafer to reduce the adhesion force between the pollutant and the wafer;
a scrub module comprising a polishing pad to scrub the wafer with a mechanical external force to remove the contaminants on the wafer surface.
Optionally, the interaction between the surfactant and the contaminants on the wafer surface is a chemical interaction or a physical interaction.
Optionally, the method further includes:
and the driving wheel is used for bearing the wafer and driving the wafer to rotate.
Optionally, the scrub module further comprises:
the driving unit is used for driving the polishing pad to rotate along the axial direction of the polishing pad; or the driving unit is used for driving the polishing pad to reciprocate along a preset path.
Optionally, the method further includes:
and the ultrasonic cleaning module is used for carrying out ultrasonic cleaning on the wafer.
Optionally, the method further includes:
and the acid cleaning module is used for washing the wafer by adopting an acid cleaning agent.
Optionally, the method further includes:
and the alkaline cleaning module is used for washing the wafer by adopting an alkaline cleaning agent.
According to the wafer cleaning method and the wafer cleaning device provided by the invention, the adhesion force between the pollutants on the surface of the wafer and the wafer is reduced by using the surfactant, so that the pollutants are more easily separated from the surface of the wafer, and then the pollutants are erased from the surface of the wafer by using the mechanical external force applied to the surface of the wafer by the polishing pad, so that most or even all of the pollutants remained on the surface of the wafer in the previous process can be removed, and the probability of the pollutants sticking back to the surface of the wafer is reduced due to the reduction of the adhesion force between the pollutants and the wafer, so that the wafer cleaning effect is improved, the residues of the pollutants on the surface of the wafer are reduced, and the smooth and stable operation of the semiconductor process is ensured. In addition, the polishing pad is used for applying mechanical external force to the surface of the wafer to remove pollutants from the surface of the wafer, and the technical problem that in the prior art, the surface of the wafer is scrubbed through a cleaning brush, and when the cleaning brush is separated from the wafer, particles are adhered to the surface of the wafer again due to the limitation of the structure of the cleaning brush, so that the surface is defective is solved.
Drawings
FIG. 1 is a flow chart of a wafer cleaning method in accordance with an embodiment of the present invention;
FIGS. 2A-2F are schematic cross-sectional views of the main processes of the embodiments of the present invention in the process of cleaning a wafer;
fig. 3 is a block diagram of a wafer cleaning apparatus according to an embodiment of the present invention.
Detailed Description
The following describes in detail embodiments of a wafer cleaning method and a wafer cleaning apparatus according to the present invention with reference to the accompanying drawings.
Fig. 1 is a flowchart of a wafer cleaning method according to an embodiment of the present invention, and fig. 2A to 2E are schematic process cross-sectional views of a wafer cleaning process according to an embodiment of the present invention. As shown in fig. 1 and fig. 2A to fig. 2F, the wafer cleaning method according to the present embodiment includes the following steps:
step S11, providing a wafer to be cleaned, wherein the surface of the wafer 20 has contaminants 21, as shown in fig. 2A.
Specifically, the wafer 20 is subjected to one or more process steps prior to cleaning, resulting in the wafer 20 having the contaminants on its surface that remain from the process steps. For example, the wafer 20 includes a substrate 201 and an oxide layer 202 located on the surface of the substrate 201, and the oxide layer 202 can be thinned and the surface of the oxide layer 202 can be planarized by performing chemical mechanical polishing on the oxide layer 202. After the chemical mechanical polishing process is finished, the surface of the oxide layer 202 has contaminants 21, and the contaminants 21 include residual polishing slurry, debris generated during the chemical mechanical polishing process, and the like.
Step S12, spraying a surfactant onto the surface of the wafer 20 while scrubbing the surface of the wafer 20 with the polishing pad 23, wherein the surfactant can react with the contaminants 21 on the surface of the wafer 20 to reduce the adhesion between the contaminants 21 and the wafer 20, thereby removing the contaminants 21 on the surface of the wafer 20.
Specifically, by using a surfactant as a cleaning agent, the effect of reducing the adhesion between the contaminant 21 and the wafer 20 is achieved by utilizing the action between the surfactant and the contaminant 21, so that the contaminant 21 is more easily detached from the surface of the wafer 20. In combination with the mechanical external force applied by the polishing pad 23 to the surface of the wafer 20, the surface of the wafer 20 to be cleaned is scrubbed, and the contaminants 21 can be separated from the wafer 20, so that the effect of removing the contaminants 21 on the surface of the wafer 20 is achieved. Moreover, because the adhesion force between the contaminants 21 and the wafer 20 is reduced, the contaminants removed by the mechanical external force are difficult to adhere back to the surface of the wafer 20, thereby avoiding secondary pollution of the wafer 20, improving the cleaning effect of the wafer 20, and ensuring continuous and stable subsequent semiconductor manufacturing process.
Figure 2B is a side view of a wafer surface being cleaned using a surfactant in combination with a pad scrub. Specifically, as shown in fig. 2B, the surfactant 221 is sprayed to the surface of the wafer 20 through the first spraying pipe 22, so that the surface of the wafer 20 to be cleaned is covered by the surfactant 221. Meanwhile, the surface of the wafer 20 to be cleaned is scrubbed by using the polishing pad 23, and the contaminants 21 on the surface of the wafer 20 are removed by the action of friction.
In this embodiment, the polishing pad 23 is adopted to apply a mechanical external force to the contaminants on the surface of the wafer 20, and the surface of the polishing pad 23 contacting the wafer 20 is always the same plane (i.e., the polishing surface of the polishing pad 23) on the polishing pad 23, so that the contaminants 21 do not stick back to the surface of the wafer 20 from the polishing pad 23 at the moment the polishing pad 23 is separated from the wafer 20, thereby fundamentally preventing the wafer 20 from being secondarily contaminated. The polishing surface of the polishing pad 23 has a plurality of protrusions, and the plurality of protrusions are arranged in parallel in a direction parallel to the polishing surface. The contaminants 21 on the surface of the wafer 20 are removed by friction (i.e., mechanical external force) of the protrusions against the surface of the wafer 20.
Optionally, the interaction between the surfactant and the contaminant 21 on the surface of the wafer 20 is a chemical interaction or a physical interaction. The specific form of interaction between the surfactant and the contaminant 21 depends on the type of surfactant and the type of contaminant 21.
Optionally, the specific steps of scrubbing the surface of the wafer 20 by using the polishing pad 23 include:
the wafer 20 and the polishing pad 23 are driven to rotate respectively, and the wafer 20 and the polishing pad 23 rotate in the same direction.
For example, as shown in fig. 2B, during the wafer scrubbing process using the polishing pad 23, the wafer 20 is driven to rotate along a first axis by the driving wheel 24, the first axis is an axis parallel to the Z-axis direction and passing through the center of the wafer 20. The polishing pad 23 rotates on its own axis along a second axis which is an axis parallel to the Z-axis direction and passing through the center of the polishing pad 23, i.e., the first axis is parallel to the second axis. The wafer 20 rotates clockwise along the first axis, and the polishing pad 23 rotates clockwise along the second axis; alternatively, the wafer 20 rotates counterclockwise along the first axis, and the polishing pad 23 rotates counterclockwise along the second axis. The rotation speed of the wafer 20 is different from that of the polishing pad 23.
In other embodiments, the step of scrubbing the surface of the wafer 20 with the polishing pad 23 comprises:
the wafer 20 is driven to rotate, and the polishing pad 23 is driven to reciprocate on the surface of the wafer 20 along a predetermined path.
For example, as shown in fig. 2B, during the wafer scrubbing process using the polishing pad 23, the wafer 20 is driven to rotate along a first axis by the driving wheel 24, the first axis is an axis parallel to the Z-axis direction and passing through the center of the wafer 20. The polishing pad 23 performs a reciprocating translational motion on the surface of the wafer 20 along a predetermined path, i.e., the polishing pad 23 oscillates on the surface of the wafer 20 along a predetermined path.
Optionally, the wafer 20 includes a substrate 201 and an oxide layer 202 located on the substrate 201, and the contaminant 21 is a contaminant remaining after the oxide layer 202 is subjected to a chemical mechanical polishing process; the specific steps of scrubbing the wafer 20 with a surfactant in combination with a mechanical external force include:
the oxide layer 202 is scrubbed using a surfactant in combination with a mechanical external force.
Optionally, the polishing slurry used in the chemical mechanical polishing process is cerium dioxide, and the surfactant is a sulfate or a sulfonate.
Chemical mechanical polishing is a process in which a chemical reaction process and a mechanical polishing process work together. During the grinding process, the grinding head applies a certain pressure on the back surface of the wafer, so that the front surface of the wafer is tightly attached to the grinding pad. The polishing pad rotates, and the polishing head drives the wafer and the polishing pad to rotate in the same direction, so that the front surface of the wafer and the surface of the polishing pad generate mechanical friction. In the grinding process, a film layer with a certain thickness on the surface of the wafer is removed through a series of complicated mechanical and chemical actions, so that the purpose of flattening the wafer is achieved.
Fig. 2C is a schematic view of the case where the oxide layer after the chemical mechanical polishing is treated with a surfactant. For example, after the oxide layer 202 is polished by using ceria as a polishing liquid in a chemical mechanical polishing process, the surface of the oxide layer 202 is electronegative, and residual cerium ions (Ce) are remained4+) The surface active agent 221 is a sulfate or a sulfonate with electronegativity, which is used for positive electricity, the surface active agent 221 with electronegativity can chemically react with cerium ions with positive electricity, so as to reduce the adhesion of the cerium ions on the surface of the wafer 20, and then the residual cerium dioxide polishing solution can be removed from the surface of the wafer 20 by applying a mechanical external force through the polishing pad 23.
The time for scrubbing the wafer 20 by using the surfactant in combination with the mechanical external force can be adjusted according to different process requirements, for example, the scrubbing time can be controlled within a range of 30s to 300 s.
Optionally, the mass concentration of the surfactant is less than 1%. The step of scrubbing with the surfactant in combination with mechanical external force may be carried out at ambient temperature, for example in the temperature range of 15 ℃ to 35 ℃.
Optionally, after the wafer is scrubbed by using a surfactant and combining with a mechanical external force, the method further includes the following steps:
the wafer 20 is cleaned using an ultrasonic cleaning process.
Figure 2D is a side view of a wafer being cleaned using an ultrasonic cleaning process. The ultrasonic cleaning described in this embodiment may be megasonic cleaning. Bubbles generated by the ultrasonic wave 25 flow on the wafer 20 by megasonic cleaning to carry away the contaminants 21 remaining on the surface of the wafer 20. The cleaning time of the ultrasonic cleaning can be in the range of 30s to 300 s. TMAH (tetramethylammonium hydroxide) with the mass concentration of less than 1% can be adopted as the ultrasonic cleaning solution, and the temperature range during cleaning is between 25 and 35 ℃. Or the solution for ultrasonic cleaning adopts SC1 (mixture of ammonia water, hydrogen peroxide and water) solution, and the temperature range for cleaning is between 20 ℃ and 80 ℃.
Optionally, after the wafer 20 is cleaned by using the ultrasonic cleaning process, the method further includes the following steps:
the wafer 20 is rinsed with an acidic rinse.
Optionally, the specific steps of washing the wafer 20 with an acidic cleaning agent include:
and spraying an acidic cleaning agent to the surface of the wafer 20 while driving the wafer 20 to rotate, so as to remove a natural oxidation layer on the surface of the wafer.
Fig. 2E is a side view of the wafer 20 being rinsed with an acidic rinse. As shown in fig. 2E, the acidic cleaning agent 261 is sprayed onto the surface of the wafer 20 through the second spray pipe 26, and at the same time, the wafer 20 is driven by the driving wheel 24 to rotate in the XY plane (i.e., rotate along an axis parallel to the Z axis and passing through the center of the wafer 20). The acidic cleaning solution has an etching effect on a native oxide layer (e.g., a silicon dioxide layer formed by a native oxidation) formed on the surface of the wafer 20, and can etch away a thin native oxide layer film on the surface of the wafer 20, thereby removing relatively stubborn particles in the contaminants 21. The native oxide layer is different from the oxide layer 202 in the wafer 20, and the native oxide layer is formed on the surface of the oxide layer 202 by the contaminant particles on the surface of the wafer 20 through the native oxidation. The acidic cleaning agent can be hydrofluoric acid with the mass concentration of 0.1-1%. The acid cleaning time is controlled within a range of 5 to 60 seconds depending on the concentration of hydrofluoric acid used, and the acid cleaning is performed at normal temperature (15 to 35 ℃). In the process of performing the acid cleaning on the wafer 20, the native oxide layer is removed only by the washing action of the acid cleaning agent without using a cleaning brush.
Optionally, after the wafer 20 is rinsed with the acidic cleaning agent, the method further includes the following steps:
the wafer 20 is rinsed with an alkaline cleaner.
Optionally, no cleaning brush is used in the process of washing the wafer 20 with the alkaline cleaning agent.
Fig. 2F is a side view of the wafer 20 being rinsed with an alkaline cleaner. As shown in fig. 2F, the alkaline cleaner 271 is sprayed onto the surface of the wafer 20 through the third spray pipe 27, and at the same time, the wafer 20 is driven by the driving wheel 24 to rotate in the XY plane (i.e., rotate along an axis parallel to the Z axis and passing through the center of the wafer 20). The alkaline cleaning agent is mainly used for neutralizing the acid cleaning agent remained on the surface of the wafer 20, so as to avoid further erosion of the wafer 20 by the remained acid cleaning agent, and recover the alkaline property of the surface of the wafer 20. The time of alkaline cleaning can be controlled within the range of 30s to 300 s. The alkaline cleaning agent can be TMAH (tetramethylammonium hydroxide) with the mass concentration of less than 0.1%, and the cleaning temperature is normal temperature. Alternatively, the alkaline cleaning agent can be a solution of SC1 (ammonia, a mixture of hydrogen peroxide and water), and the temperature range during cleaning is between 20 ℃ and 80 ℃.
In the process of cleaning the wafer 20 with the alkaline cleaning agent, the cleaning brush is not used, that is, the acidic cleaning agent remaining on the surface of the wafer is removed only by the action of the alkaline cleaning agent and the acidic cleaning agent remaining on the surface of the wafer 20 and the centrifugal force generated by the rotation of the wafer 20.
Moreover, the embodiment also provides a wafer cleaning device. Fig. 3 is a block diagram of a wafer cleaning apparatus according to an embodiment of the present invention. The wafer cleaning apparatus provided in the present embodiment may use the wafer cleaning method shown in fig. 1 and fig. 2A to fig. 2F to clean the wafer. As shown in fig. 1, fig. 2A to fig. 2F and fig. 3, the wafer cleaning apparatus according to the present embodiment includes:
a spraying module 31, wherein the spraying module 31 is used for spraying a surfactant to the wafer 20 with the pollutant 21 on the surface, and the surfactant can act with the pollutant 21 on the surface of the wafer 20 to reduce the adhesion force between the pollutant and the wafer 20;
a scrub module 32 comprising a polishing pad 23, wherein the polishing pad 23 is used for scrubbing the wafer 20 by using a mechanical external force, so as to remove the contaminants on the surface of the wafer 20.
Optionally, the interaction between the surfactant and the contaminant 21 on the surface of the wafer 20 is a chemical interaction or a physical interaction.
Optionally, the wafer cleaning apparatus further includes:
and the driving wheel 24 is used for bearing the wafer 20 and driving the wafer 20 to rotate.
Optionally, the scrub module 32 further comprises:
a driving unit 321 for driving the polishing pad 23 to rotate in an axial direction thereof; alternatively, the driving unit 321 is configured to drive the polishing pad 23 to reciprocate along a predetermined path.
Optionally, the wafer cleaning apparatus further includes:
an ultrasonic cleaning module 33, configured to perform ultrasonic cleaning on the wafer 20.
Optionally, the wafer cleaning apparatus further includes:
and an acid cleaning module 34 for rinsing the wafer 20 with an acid cleaning agent.
Optionally, the wafer cleaning apparatus further includes:
and the alkaline cleaning module 35 is used for washing the wafer 20 by using an alkaline cleaning agent.
The wafer cleaning device may further include a control module 30, wherein the control module 30 is connected to the spraying module 31, the scrubbing module 32, the ultrasonic cleaning module 33, the acidic cleaning module 34, and the alkaline cleaning module 35, and is configured to adjust working states (including an open state and a closed state) of the control module 30 connected to the spraying module 31, the scrubbing module 32, the ultrasonic cleaning module 33, the acidic cleaning module 34, and the alkaline cleaning module 35, respectively, so as to ensure that a wafer cleaning process is performed smoothly.
According to the wafer cleaning method and the wafer cleaning device provided by the embodiment, the adhesion force between the pollutants on the surface of the wafer and the wafer is reduced by using the surfactant, so that the pollutants are more easily separated from the surface of the wafer, and then the pollutants are erased from the surface of the wafer by using the mechanical external force applied to the surface of the wafer by the polishing pad, so that most or even all of the pollutants remained on the surface of the wafer in the previous process can be removed, and the probability of the pollutants sticking back to the surface of the wafer is reduced due to the reduction of the adhesion force between the pollutants and the wafer, so that the wafer cleaning effect is improved, the residues of the pollutants on the surface of the wafer are reduced, and the smooth and stable proceeding of the semiconductor process is ensured. In addition, the polishing pad is used for applying mechanical external force to the surface of the wafer to remove pollutants from the surface of the wafer, and the technical problem that in the prior art, the surface of the wafer is scrubbed through a cleaning brush, and when the cleaning brush is separated from the wafer, particles are adhered to the surface of the wafer again due to the limitation of the structure of the cleaning brush, so that the surface is defective is solved.
The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.
Claims (19)
1. A wafer cleaning method is characterized by comprising the following steps:
providing a wafer to be cleaned, wherein the surface of the wafer is provided with pollutants;
and spraying a surfactant to the surface of the wafer while scrubbing the surface of the wafer by using a polishing pad, wherein the surfactant can act on the pollutants on the surface of the wafer to reduce the adhesion between the pollutants and the wafer, so that the pollutants on the surface of the wafer are removed.
2. The wafer cleaning method as claimed in claim 1, wherein the action between the surfactant and the contaminants on the wafer surface is a chemical action or a physical action.
3. The method of claim 1, wherein the step of scrubbing the surface of the wafer with the polishing pad comprises:
the wafer and the polishing pad are driven to rotate respectively, and the rotation directions of the wafer and the polishing pad are the same.
4. The method of claim 1, wherein the step of scrubbing the surface of the wafer with the polishing pad comprises:
and driving the wafer to rotate and driving the polishing pad to reciprocate on the surface of the wafer along a preset path.
5. The wafer cleaning method as claimed in claim 1, wherein the wafer comprises a substrate and an oxide layer on the substrate, and the contaminant is a contaminant remaining after the oxide layer is subjected to a chemical mechanical polishing process; the specific steps of scrubbing the wafer by adopting a surfactant and combining with mechanical external force comprise:
and scrubbing the oxide layer by adopting a surfactant and combining with mechanical external force.
6. The wafer cleaning method according to claim 5, wherein the polishing slurry used in the chemical mechanical polishing process is ceria, and the surfactant is a sulfate or a sulfonate.
7. The wafer cleaning method as claimed in claim 6, wherein the mass concentration of the surfactant is less than 1%.
8. The wafer cleaning method as claimed in claim 1, wherein after scrubbing the wafer by using a surfactant in combination with a mechanical external force, the method further comprises the following steps:
and cleaning the wafer by adopting an ultrasonic cleaning process.
9. The wafer cleaning method as claimed in claim 8, wherein after the wafer is cleaned by the ultrasonic cleaning process, the method further comprises the following steps:
and washing the wafer by adopting an acid cleaning agent.
10. The wafer cleaning method as claimed in claim 9, wherein the step of rinsing the wafer with an acidic cleaning agent comprises:
and spraying an acid cleaning agent to the surface of the wafer while driving the wafer to rotate, so as to remove a natural oxidation layer on the surface of the wafer.
11. The wafer cleaning method as claimed in claim 9, wherein after the wafer is rinsed with the acidic cleaning agent, the method further comprises the steps of:
and washing the wafer by adopting an alkaline cleaning agent.
12. The method for cleaning the wafer as claimed in claim 11, wherein no cleaning brush is used in the process of washing the wafer by using the alkaline cleaning agent.
13. A wafer cleaning apparatus, comprising:
the spraying module is used for spraying a surfactant to a wafer with a pollutant on the surface, and the surfactant can act on the pollutant on the surface of the wafer to reduce the adhesion force between the pollutant and the wafer;
a scrub module comprising a polishing pad to scrub the wafer with a mechanical external force to remove the contaminants on the wafer surface.
14. The wafer cleaning apparatus as claimed in claim 13, wherein the interaction between the surfactant and the contaminants on the wafer surface is a chemical interaction or a physical interaction.
15. The wafer cleaning apparatus as recited in claim 13, further comprising:
and the driving wheel is used for bearing the wafer and driving the wafer to rotate.
16. The wafer cleaning apparatus as claimed in claim 13, wherein the scrub module further comprises: the driving unit is used for driving the polishing pad to rotate along the axial direction of the polishing pad; or the driving unit is used for driving the polishing pad to reciprocate along a preset path.
17. The wafer cleaning apparatus as recited in claim 13, further comprising:
and the ultrasonic cleaning module is used for carrying out ultrasonic cleaning on the wafer.
18. The wafer cleaning apparatus as recited in claim 13, further comprising:
and the acid cleaning module is used for washing the wafer by adopting an acid cleaning agent.
19. The wafer cleaning apparatus as recited in claim 13, further comprising:
and the alkaline cleaning module is used for washing the wafer by adopting an alkaline cleaning agent.
Priority Applications (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110294823.XA CN113078078A (en) | 2021-03-19 | 2021-03-19 | Wafer cleaning method and wafer cleaning device |
| PCT/CN2021/113075 WO2022193542A1 (en) | 2021-03-19 | 2021-08-17 | Wafer cleaning method and wafer cleaning apparatus |
| US17/457,799 US20220301892A1 (en) | 2021-03-19 | 2021-12-06 | Wafer cleaning method and wafer cleaning apparatus |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202110294823.XA CN113078078A (en) | 2021-03-19 | 2021-03-19 | Wafer cleaning method and wafer cleaning device |
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| CN113078078A true CN113078078A (en) | 2021-07-06 |
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| CN202110294823.XA Pending CN113078078A (en) | 2021-03-19 | 2021-03-19 | Wafer cleaning method and wafer cleaning device |
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| CN (1) | CN113078078A (en) |
| WO (1) | WO2022193542A1 (en) |
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| CN115256234A (en) * | 2022-09-28 | 2022-11-01 | 华海清科股份有限公司 | Wafer thinning equipment with dresser belt cleaning device |
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| WO2022193542A1 (en) | 2022-09-22 |
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